Method of and arrangement for producing crimped flat material



April 20, 1965 P. A. MULLER 3,179,024

METHOD OF AND ARRANGEMENT FOR PRODUCING CRIMPED FLAT MATERIAL OriginalFiled April 18, 1955 2 Sheets-Sheet 1 I Fig.3 Fig.5 u-u- M 1N VEN TOR.

ATTORNEKS April 0,1965 P. A. MULLER 3,

METHOD OF AND ARRANGEMENT FOR PRODUCING CRIMPED FLAT MATERIAL OriginalFiled April '18, 1955 2 sheets-sheet 2 United States Patent "ice tionJan. 21, 1963, Ser. No. 252,909

17 Claims. (Cl. 93-1) The present invention relates to a method of andan i 4 arrangement for producing crimped, i.e., grooved, fiat material,particularly crimped paper webs for smoke filters. This application is adivision of my copending application Serial No. 841,919, filed September2, 1959, which is a division of application Serial No. 502,016, filedApril 18, 1955, now Patent No. 2,995,481, which was acontinuation-in-part of my application Serial No. 447,478, filed August3, 1954, now Patent No. 2,847,086.

Crimped papers are already known and, besides other purposes, are usedto an important extent for the manufacture of filters for tobacco,particularly for cigarettes. Since, with such filters, flat webs ofpaper have to be shaped into cylindrical plugs, the paper used must haveonly a slight rigidity at least in one direction. A noncrimped web ofpaper would, on being compressed into a cylindrical cord, have irregularfolds and randomly distributed bulges, which would lead to an irregularweb cross-section with hollow spaces and unconnected ducts, that is tosay, the result would be a structure completely unsuited for filteringpurposes. Crimped paper, on the other hand, does not have thesedisadvantages and for this reason paper filter plugs are almostexclusively made with such material.

The crimping of the paper web, however, also facilitates the mechanicalmanufacture of such filter plugs and,

furthermore, ensures that they will have the necessary porosity.

Crimped paper has so far been produced almost exclusively by a generallyknown method in which an endless damp webof paper runs on to a heatedcylinder, dries there-to a certain extent and is peeled off by a bluntscraper, the previously smooth paper web being upset.

of length of the final product can be stretched to three times itslength and ironed out into a smooth web, that is to say, in its crimpedstate, it is threetimes as heavy as the smooth web.

With a web of paper crimped by this method the Y crimped folds andgrooves run transverse to the direction of travel. Although crimping ofthe web is indispensable, the fact that it runs transverse to the webcomplicates both the machines for the production of filters and theprocess employed therefor. As the filter cord is produced by the placingtogether of one or several paper strips of given width, which can onlybe done vertically to the crimped, folds, strips of the aforesaid widthmust be cut off the broad crimped Webs of paper so that these stripscannot be longer than the width of the crimped web. These strips arethen fed to the gathering attachment of the filter plug machine in thelongitudinal direction, i.e., parallel to the crimped folds.

In order to make continuous production possible, such longitudinallycrimped paper strips of limitedlengthare arranged side by side and slidcontinuously into the 3,179,024 Patented Apr. 20, 1965 gatheringattachment. Apart from the cutting and conveying devices thus required,which work intermittently and cause an increased susceptibility tobreakdowns, the small length of strip provides a number of extremelytroublesome shortcomings. In order to ensure that the successive stripsare properly introduced into the gathering attachment, strips wider than4 to 5 cm. cannot be used, this, as the material required is determinedby the dimensions and thickness of the filter card, makes it necessaryto lay four to six crimped strips one on top of the other and to workthem jointly in the gathering attachment, thus complicating the feedingapparatus still further. Since no other way of continuous manufacturehas been known hitherto, extensive mechanical devices have been designedfor the purpose and used in practice. It has also already been suggestedto paste the separate crimped strips together by hand so as to permitcontinuous operation (cf. German Federal Patent No. 826,257).

Apart from this feed difficulty, however, another drawback is that thefirst and last filter of every crimped strip of limited length have tobe considered as rejects as both may contain the junction point betweensuccessive strips. This must be avoided since with strips which are notpasted together part of the filter plug may easily drop out of thecigarette and with pasted strips the filtering effect is impaired by thepasted edge.

1 terial.

Thus there exists a need for a simple method of producing fiat materialcrimped in any desired direction from a smooth web of material and foran arrangement for producing an endless longitudinally crimped web ofmaterial.

The present invention relates to a method of this sort and ischaracterized by the fact that the smooth web of material is madeyielding and is then crimped and stretched by grooving so that a unit oflength of the crimped web of material is at the most equal in Weight tothe same unit of length of the smooth web.

Furthermore, the invention relates to an arrangement for theabovementioned purpose. This arrangement is characterized by processingdevices designed to achieve a desirable yieldingness of the smooth webof material, by members for producing grooves in the web of materialwith simultaneous stretching of the latter, the grooves runningapproximately parallel to the longitudinal direction of the web ofmaterial, and by a drier for the thus crimped web of material.

The web of filtering material produced on the arrangement and by themethod according to the invention is characterized by the fact that itis an' endless web with a longitudinal structure parallel to itsdirection of travel, consisting of alternately thicker and lessthickstrip ma- A typical embodiment of the invention will now bedescribed in detail in conjunction with FIGS. 1 to-13 of the attacheddrawing in which:

FIGS. 1 and 2 are a vertical and horizontal projection respectively of atypical embodiment of the arrangement according to the invention, showndiagrammatically;

FIGS. 3 to 10 are cross-sections and horizontal projectionsrespectively, arranged in pairs; each pair is intended to indicate on anenlarged scale the appearance of the Web of material at different pointsas it passes through the arrangement;

FIGS. 11 and 12 are each cross-sections stretched, corrugated web; and

FIG. 13 shows a few samples of the material according to the invention.

The fundamental difference between the present method through a ofcrimping flat material and all previous crimping methtothe 'fact thatthe crimping process, contrary to the existing assumption, does notnecessarily result in a compression of the material per unit of length,but can also be achieved by stretching the structure of the material.This yields a web of material which, per unit of length is at the mostequal in Weight-even less. heavy in most Cases-40 the smooth web ofmaterial. In spite of this, a substantial crimping ratio can beobtained, e.g., in the order of magnitude of 1:2; so that after thecrimped web of material has been ironed smooth, it will have, per unitof length of the original web, dimensions which have become enlarged inthe same ratio. Sections of equal area of the original web of materialand of the crimped web which has been ironed smooth again will then bedifferent in weight, the ironed web being lighter in proportion to thecrimpingratio.

The crimping and stretching processes are advantageously, but notnecessarily, carried out at the same time. Accordingly, the web of flatmaterial to be treated must be previously made yielding, which can bedone'by spraying it with liquid, submitting it to steam treatment, heat:ing it, passing it through a bath of liquid or in any other suitablemanner depending on the type of material. This treatment, however, iscarried out continuously on the web of material which is moved at aconstant speed.

The flat material which has been made yielding, is subjected to acontinuous process of crimping and stretching, for instance by means ofsuitable stamping devices, grooves, being produced such that the twonarrow zones of material are kept rigid along each groove and thecentral zone inbetween is deformed. Owing to the lateral zones beingkept rigid, the central zone can only be deformed if the material in itis stretched at the same time. This process is carried out successivelyon a plurality of parallel grooves and yields a Web of material whosesurface has been enlarged at the expense of the thickness of thematerial at the point concerned. The differences in thickness transverseto the grooves of the web of material can result, as required, inthinner groove walls and thicker edges or, conversely, in thicker wallsand thinner edges (FIGS. 11 and 12).

If, by way of example, the web of material is grooved in itslongitudinal direction, it will retain after the completed crimping andstretching process approximately the same width as before. In otherwords, the web of material is grooved while preventing any substantialtransverse shrinkage so that the material is transversely stretched. Ifthe web thus crimped is ironed smooth again, the resultant width of theweb will be enlarged by the amount of the crimping ratio.

The stretchingof the flat material depends primarily on the depth of theindividual grooves and may be greater or less according to the type ofmaterial. If a Web of material has to be more deeply grooved than is compatible with its stretching capacity, grooving is carried out in severalsuccessive stages, it being possible for the web of material to have asomewhat smaller width between each two stagw. The final result willthen be a crimped web of material which, although having the desireddepth of groove, is less wide than the original smooth web; here, too,however, the surface is enlarged at the expense of the thickness of thematerial. v

The crimped web of material generally requires an aftertreatment, dryingfor instance, in order to re-harden it, and can then be divided up intonarrow strips and wound on to magazine rolls or made up into filtersimmediately. o

For certain purposes, for the production of webs of filtering materialfor instance, perforation of the flat material may be desirable. This issuitably done before the web of material has been made yielding or afterit has been re-hardened with or without aftertreatment subsequent to thecrimping and stretching process. The perforation methods suitable forthe present purpose are describedin my U.S. Patent 2,847,086 and can,mutatis mutandis, beused here. For such webs of filtering material itmay also be adayntageous to interrupt the regular i grooving of thecrimped material, which can be done by means of a second grooving withthe grooves running in a different direction. This cross grooving mustof course also be effected when the material is still yielding. Finally,it should also be pointed out that for filtering purposes the materialcan be so vigorously stretched that randomly instance, runs from thedelivery roll 2 through a perforator consisting of a toothed roller Sanda corresponding counter roller 4, or of other suitable perforatingmembers. After passing through this perforator the web of material hasragged holes as shown in FIGS. 3 and 4. The perforated web then passesinto a device 5, in which it is, for instance, moistened or treated withaqueous steam so as to give it the desired yieldingness. the tensilestrength of the web of material must of course be great enough to ensurethe faultless passage of the said material through the entirearrangement.

The web of material which has been made yielding and perforated is thendeformed in a multistage crimping and stretching apparatus 6. Here it isassumed that stamping is effected by a number of pairs of rollers, thefirst of which is designated 7, 8 and the last 9, 10. Each roller 7, 8and 9, 10 has a plurality of circumferential grooves alternating withstamping edges or lands of lesser width which project into the groovesof the opposed roller. In order to obtin a reduction in width, which ispresumed to be desirable, the distance between the stamping edges ofeach successive pair of rollers is shortened. The same effect isachieved by increasing the speed of the roller pair 9, It) in relationto that of the roller pair 7, 8. The reduction in width of the web ofmaterial will not necessarily be as large as indicated in FIGS. 1 and 2.Particularly when the material is vigorously stretched, the web widthshown by dot-dash lines will result.

FIGS. 5 and 6 illustrate the appearance of the web of material 1 afterit has passed through the firstpair of rollers 7, 8 and FIGS. 7 and 8after it has passed through the last pair of rollers 9, 10. According tothe configuration of the stamping rollers, the thickness of the materialcan be greater either at the groove edges, as shown in FIG. 11, or atthe walls, as shown in FIG. 12. The thinning of the web 1 formed bylateral stretching thereof, as well as the formation of randomlydistributed cracks produced by vigorous lateral stretching, inherentlyresults in the release of fiber ends which project from the web. Afterleaving the crimping and stretching apparatus 6 the longitudinallycorrugated and perforated web of material 1 passes through a pair ofrollers 11, 12-pricking or knurled rollers, or others ofsuitable.configurationwhich deform the regular longitudinal crimpedfolds in an irregular manner so that the longitudinal corrugated web ofmaterial possesses a plurality of longitudinal grooves which run intoone another, as indicated in FIGS. 9 and 10. Next, the web of material 1passes into an aftertreatment apparatus, which here consists of a dryingplate 13 with electric heating element 14. The longitudinally crimpedweb of material 1 can be easily damaged in its yielding state and musttherefore not be pressed against the drying plate 13 by mechanicalmeans. Instead, an air stream directed via the nozzles 15 against theweb of material 1 is provided for the purpose. This air stream can, inits turn, be heated if desired or can also be used to cool the web ofmaterial 1. c Q

Normally, a reduction in the width of the longitudinally crimped web ofmaterial occurs while the latter is being dried (not illustrated inFIGS. 1 and 2). If desired, this effect can be enhanced still further bygently compressing the web of material from the side, e.g., by means oflateral Furthermore,

streams of compressed air ejected from special nozzles. The extent ofthe lateral contraction of the drying web also depends, of course, onthe type of material, as well as on the changes in thickness caused bythe stretching process, which changes are, in their turn, determined bythe shape of the stamping grooves. I

If desired, the hardened web of material 1 coming from theaftertreatment apparatus can pass through a second perforator consistingof the rollers 16, 17, in which case the first perforator 3, 4 maypossibly be omitted. The web of material 1, which has thus received itsfinal form, is now subdivided by rotating cutter blocks 18, 19 intothree strips 1a, 1b, which are wound on to' magazine spools 20, 21, 22.

The arrangement shown in FIGS. 1 and 2 can be substantially simplified,according to the type of the web of material to be worked and thepurpose intended for the strip filtering material produced. By way ofexample, the perforators 3, 4 and 16, 17 can be completely dispensedwith, particularly, if randomly distributed cracks and holes areproduced by adequately vigorous stretching of the material. Furthermore,grooving with only one pair of stamping rollers 7, 8 already yields aperfectly usable, longitudinally corrugated web of material, the widthof the original smooth web remaining virtually unchanged. In this case,to be sure, it is advisable to employ a fineknurled pair of rollers 11,12 so as to avoid through longitudinal ducts.

FIG. 12 shows a photograph of four samples of material, A, B, C and Dwhich were produced with an arrangement of the type described above andhaving only one pair of stamping rollers. With all four samples crimpingwas effected in the same maner; with samples A and B, however,perforation was effected before or after the crimping and stretchingprocess respectively, but treatment with a knurled roller was dispensedwith. C and D are samples of a crimped and stretched web of materialsubsequently treated with a coarse or fine knurled roller respectively.In all cases the longitudinal grooving is clearly visible, the materialherea thinblotting paperbeing so vigorously stretched that large cracksoccur, which greatly facilitates the gathering of the webs of material,which is done transverse to the longitudinal direction of the grooves,and yields highly effective filter cords. In addition the longitudinalstructure consisting of an alternately larger and smaller materialthickness transverse to the longitudinal direction of the groove isclearly recognizable.

What is claimed is:

1. The method of treating an elongated web of fibrous strip material torender the same particularly adapted to be gathered laterally, formedinto a cylindrical rod, and enclosed in a wrapper to make a filter fortobacco smoke, the steps comprising: treating said web to soften andrender the same yielding; longitudinally grooving the softened web whilepreventing any substantial transverse shrinkage thereof to both formtherein a plurality of closely spaced longitudinal corrugations. andlaterally stretch the material of the softened web to form thereinlaterally spaced longitudinal zones of lesser thickness where the fibersof the material are somewhat separated; and treating the corrugatedstretched web to reharden the same and set said corrugations therein.

2. The method of treating an elongated web of fibrous strip material torender the same particularly adapted to be gathered laterally, formedinto a cylindrical rod, and

. corrugated torn web to reharden the same and set the enclosed in awrapper to make a filter for tobacco smoke,

the steps comprising: treating said web to soften and render the sameyielding; longitudinally grooving the'softened web while preventing anysubstantial transverse shrinkage thereof to both form therein aplurality of closely spaced longitudinal corrugations and laterallycorrugations therein.

3. The method defined in claim 2 in which the softening step comprisesmoistening the web and the rehardening step comprises drying said web.

4; The method defined in claim 2 including the additional step prior tothe rehardening step of somewhat flattening the corrugated torn web.

5. The method defined in claim 2 in which the softening step comprisesmoistening the web andthe rehardening step comprises drying said web,and including the additional step prior to the rehardening step ofsomewhat flattening the corrugated torn web.

6. The method defined in claim 2 including the additional step,subsequent to the grooving and stretching step, of somewhat flatteningthe corrugated torn web.

7. Apparatus for treating an elongated web of fibrous strip material torender the same particularly adapted to be gathered laterally, formedinto a cylindrical rod, and enclosed in a wrapper to make a filter fortobacco smoke, comprising: means for treating the web to soften andrender the same yielding; roller means for simultaneously longitudinallygrooving and laterally stretching the material of the web to providetherein a plurality of both closely spaced longitudinal corrugations andlaterallyspaced longitudinal zones of lesser thickness where the fibersof the material are somewhat separated, said roller means including atleast one pair of rollers each of rigid material and having a pluralityof circumferential grooves separated by lands of lesser width whichproject into the grooves on the other roller of said pair; and means fortreating the grooved and stretched web to reharden the same and set saidcorrugations therein.

8. Apparatus for treating an elongated web of fibrous strip material torender the same particularly adapted to be gathered laterally, formedinto a cylindrical rod, and enclosed in a wrapper to make a filter fortobacco smoke, comprising: means for treating the web to soften andrender the same yielding; roller means for simultaneously longitudinallygrooving and laterally stretching the material of the web to providetherein a plurality of both closely spaced longitudinal corrugations andrandomly distributed discontinuous longitudinal tears, said roller meansincluding at least one pair of rollers each of rigid material and havinga plurality of circumferential grooves separated by lands of lesserwidth which project into the grooves on the other roller of said pair;and means for treating the grooved and stretched web to reharden thesame and set said corrugations therein.

9. The structure defined in claim 8 in which the softening meanscomprises means for moistening the web.

10. The structure defined in claim 8 in which the softening meanscomprises means for moistening the web and the rehardening meanscomprises means for drying the web.

11. The structure defined in claim 8 including means for somewhatcompressing the grooved and stretched web in advance of the rehardeningmeans.

12. The structure defined in claim 8 in which the roller means includesat least two successive pairs of rollers, the width of the grooves onthe rollers on each succeeding pair being less than the width of thegrooves on the rollers of the preceding pair.

13. The structure defined in claim 8 in which the softening meanscomprises means for moistening the web and the rehardening meansincludes means defining a smooth fiat heated surface and means forblowing air against one side of the web to pneumatically press thelatter against said surface.

14. The structure defined in claim 13 including means for blowing airlaterally against the side edges of the web to reduce the width thereof.

15. The structure defined in claim 8 including means for somewhatcompressing the grooved and stretched web following the grooving andstretching means.

16. Process of manufacturing an elongated strip of cellulosic materialparticularly adapted for the formation of filters for tobacco smoke,comprising the steps of: grooving paper strip longitudinally Whilepreventing any substantial transverse shrinkage thereof to provide stripcharacterized by a plurality of parallel connected loops each having aridge portion, the adjacent ridges being faced in opposite directions,and the fibers of said strip being at'least partially pulled apartlaterally thereof so that said strip has projecting fiber ends on theouter surface of said ridge portions; and flattening the grooved stripsomewhat to decrease its thickness.

17. Process of manufacturing an elongated rod of cellulosic materialadapted for the efficient filtration of tobacco smoke comprising thesteps of: grooving the paper strip longitudinally while preventing anysubhaving projecting fiber ends on the outer surface thereof;

compressing the grooved strip to flatten the said loops somewhat; andconsolidating said strip to form a substantially cylindrical rodlongitudinally permeable to gases.

References Cited by the Examiner UNITED STATES PATENTS 8/25 Lorenz. 7/39Davidson.

FRANK E. BAILEY, Primary Examiner.

1. THE METHOD OF TREATING AN ELONGATED WEB OF FIBROUS STRIP MATERIAL TORENDER THE SAME PARTICULARLY ADAPTED TO BE GATHERED LATERALLY, FORMEDINTO A CYLINDRICAL ROD, AND ENCLOSED IN A WRAPPER TO MAKE A FILTER FORTOBACCO SMOKE, THE STEPS COMPRISING: TREATING SAID WEB OF SOFTEN ANDRENDER THE SAME YIELDING; LONGITUDINALLY GROOVING THE SOFTENED WEB WHILEPREVENTING ANY SUBSTANTIAL TRANSVERSE SHRINKAGE THEREOF OF BOTH FORMTHEREIN A PLURALITY OF CLOSELY SPACED LONGITUDINAL CORRUGATIONS ANDLATERALLY STRETCH THE MATERIAL OF THE SOFTENED WEB TO FORM THEREINLATERALLY SPACED LONGITUDINAL ZONEZ OF LESSER THICKNESS WHERE THE FIBERSOF THE MATERIAL ARE SOMEWHAT SEPARATED; AND TREATING THE CORRUGATEDSTRETCHED WEB TO REHARDEN THE SAME AND SET SAID CORRUGATIONS THEREIN.